XIV Opinion, Ideology, and Population Problems-Some Sources of Domestic and Foreign Opposition to Birth Control J. Mayone Stycos The success of efforts to deal with the problem of world population growth will depend heavily on the extent to which national populations and their leaders are convinced of the seriousness of the problem. This study attempts to assess differences in opinion on population problems among nations and to explicate some of the sources of resistance to family planning among subna-tional groups in the western hemisphere. Opinion on any public issue may conveniently be classified as public or private opinion and according to whether it refers to the opinion of elites or the general population. Data for the resulting four types are found in the following characteristic sources: Public Private Elites (1) Newspapers (3) Unstructured Books interview General Population (2) "Inquiring Photographer" (4) Poll type type interview interview It is usually assumed that the "private, anonymous, and confidential" interview provides us with the most "valid" data, or at least the data which best predict behavior. However, the public opinion of politicians or other public figures is certainly more predictive of their behavior than their private opinions which may be almost irrelevant as predictors of their behavior, just as the articulations of an Indian woman in the presence of her in-laws might be a better predictor of her fertility than her more "honest" private thoughts articulated to a stranger with a notebook. Unfortunately, opinion data in the /. Mayonne Stycos is Director of the International Population Program and Professor of Sociology at Cornell University.York Abortion Law Survey," Amer J Obstet Gynec, 93, 1965. p. 1182.